import android.content.Context;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.widget.ImageView;

import android.widget.ScrollView;

import android.widget.Scroller;

/**

 * 阻尼效果的scrollview

 */

public class DampView extends ScrollView {

    /** 该属性具体参数 怎么控制  未解！！！！*/

    private static final int LEN = 0xc8;

    /** 回弹时所用的时间 */

    private static final int DURATION = 200;

    // private static final int MAX_DY = 200;

    /** 最大Y坐标 其值一般设定为Scroller对应控件的高度 */

    private static final int MAX_DY = 200;

    private Scroller mScroller;

    TouchTool tool;

    int left, top;

    float startX, startY, currentX, currentY;

    int imageViewH;

    int rootW, rootH;

    ImageView imageView;

    boolean scrollerType;

    public DampView(Context context, AttributeSet attrs, int defStyle) {

        super(context, attrs, defStyle);

    }

    public DampView(Context context, AttributeSet attrs) {

        super(context, attrs);

        mScroller = new Scroller(context);

    }

    public DampView(Context context) {

        super(context);

    }

    public void setImageView(ImageView imageView) {

        this.imageView = imageView;

    }

    float curY;

    @Override

    public boolean dispatchTouchEvent(MotionEvent event) {

        int action = event.getAction();

        if (!mScroller.isFinished()) {

            return super.onTouchEvent(event);

        }

        currentX = event.getX();

        currentY = event.getY();

        imageView.getTop();

        switch (action) {

            case MotionEvent.ACTION_DOWN:// 变量赋初始值

                left = imageView.getLeft();

                top = imageView.getBottom();

                rootW = getWidth();

                rootH = getHeight();

                imageViewH = imageView.getHeight();

                startX = currentX;

                startY = currentY;

                tool = new TouchTool(imageView.getLeft(), imageView.getBottom(),

                        imageView.getLeft(), imageView.getBottom() + LEN);

                break;

            case MotionEvent.ACTION_MOVE:

                if (imageView.isShown() && imageView.getTop() >= 0) {

                    if (tool != null) {

                        int t = tool.getScrollY(currentY - startY);

                        if (t >= top && t <= imageView.getBottom() + LEN) {

                            android.view.ViewGroup.LayoutParams params = imageView

                                    .getLayoutParams();

                            params.height = t;// 改变高度

                            imageView.setLayoutParams(params);

                        }

                    }

                    scrollerType = false;

                }

                break;

            case MotionEvent.ACTION_UP:

                scrollerType = true;

                // 松手后 回弹

                // 开始一个动画控制，由(startX , startY)在duration时间内前进(dx,dy)个单位

                // ，即到达坐标为(startX+dx , startY+dy)处

                mScroller.startScroll(imageView.getLeft(), imageView.getBottom(),

                        0 - imageView.getLeft(),

                        imageViewH - imageView.getBottom(), DURATION);

                invalidate();

                break;

        }

        return super.dispatchTouchEvent(event);

    }

    // //该mScroller针对于imageView的变化

    // 被父视图调用，用于必要时候对其子视图的值（mScrollX和mScrollY）

    // 进行更新。典型的情况如：父视图中某个子视图使用一个Scroller对象来实现滚动操作，会使得此方法被调用。

    @Override

    public void computeScroll() {

        if (mScroller.computeScrollOffset()) {

            int x = mScroller.getCurrX();

            int y = mScroller.getCurrY();// ImageView的当前Y坐标

            imageView.layout(0, 0, x + imageView.getWidth(), y);//使imageView本身做相应变化

            invalidate();

            // 滑动还未完成时，手指抬起时，当前y坐标大于其实imageView的高度时

            //设定imageView的布局参数  作用：使除imageView之外的控件做相应变化

            if (!mScroller.isFinished() && scrollerType && y > MAX_DY) {

                android.view.ViewGroup.LayoutParams params = imageView

                        .getLayoutParams();

                params.height = y;

                imageView.setLayoutParams(params);

            }

//                invalidate();

        }

    }

    public class TouchTool {

        private int startX, startY;

        public TouchTool(int startX, int startY, int endX, int endY) {

            super();

            this.startX = startX;

            this.startY = startY;

        }

        public int getScrollX(float dx) {

            int xx = (int) (startX + dx / 2.5F);

            return xx;

        }

        public int getScrollY(float dy) {

            int yy = (int) (startY + dy / 2.5F);//手势滑动距离/2.5 才是屏幕滑动的距离  此内部类主要做此用

            return yy;

        }

    }

}

<?xml version="1.0" encoding="utf-8"?>

<de.hdodenhof.damp.DampView

    xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/dampview"

    android:layout_width="match_parent"

    android:layout_height="match_parent">

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:orientation="vertical" >

        <!--此处必须设置imageview的scaleType为centerCrop,当然在代码中设置也可以-->

        <ImageView

            android:id="@+id/img"

            android:layout_width="match_parent"

            android:layout_height="200dp"

            android:scaleType="centerCrop"

            android:src="@drawable/bg_geren" />

    </LinearLayout>

</de.hdodenhof.damp.DampView>

import android.os.Bundle;

import android.support.v7.app.AppCompatActivity;

import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {

    private ImageView img;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        setupView();

    }

    public void setupView() {

        img = (ImageView) findViewById(R.id.img);

        DampView view = (DampView) findViewById(R.id.dampview);

        view.setImageView(img);

    }

}